Heretofore it has been well known that the manufacture of pneumatic tires requires body plies laid up on a tire building drum in the tire building process. It has been known in the art that tire or body plies are made by cutting fixed lengths from a web of elastomeric material such rubber having cords of wire or other suitable reinforcing material imbedded longitudinally therein. Fixed lengths of such elastomeric reinforced material are cut from the web, rotated 90.degree., and lapped upon each other to form a body ply web in which the cords are transverse with respect to the web rather than running longitudinally therewith.
The lap splices in the body ply web are critical for assurance of tire uniformity, as well as the absence of anomalies therein. It is well known in the art that each such splice should substantially replicate every other splice and be of the same uniform width across the web. In other words, the splice width should be consistent along the length of the splice, and should be substantially identical to the other splices within the web. It is typically most desirable that the splices be not only of minimum width, but also that they not be canted or skewed.
In the known art, splices are generally made by hand in an assembly line environment. Each worker makes the splice by personal "feel," relying primarily upon his own experience to assure that the overlapped ply splice is of proper width and uniform dimensions.
It has been found that small departures from splice uniformity can become prominent over the course of the work shift. An individual worker may subconsciously allow the lap splice to expand in width and, over a course of time, subsequent splices may become even wider and run out of tolerance. Effectively, the workers allow the prior splices which they have made to represent the standard for current and subsequent splices to be made. Accordingly, the "standard" may grow or shrink with time to a point where the "standard" is actually outside the specification limits for the body ply splice.
There is a need in the art for a system which provides for continued monitoring of ply splices as same are being made. There is a further need in the art for such a system which will provide an indication to the operator or worker whether the splice just made is within tolerances, or above or below nominal deviations of the lap splice width. Additionally, there is a need in the art for such a system which will provide for an indication of splice width variations from one edge of the web to the other. More specifically, there is a need in the art for such a system which allows a worker to continually monitor the geometry of the splices being made during the actual manufacturing operation and at processing line speeds so that he may be informed as to whether such splices are unacceptably deviating from specification tolerances, or if they are approaching such deviation. Finally, there is a need in the art for such a system which is conducive to implementation in an automated splicing operation in which a feed back loop may adjust splice width during the manufacturing process.